Hot answers tagged

17

Use the jumper battery to start the engine, then disconnect it and leave the engine running (with no current drain such as lights, heater fan, radio, etc). The car should charge its own battery to 80% charge in about two hours (assuming the battery and alternator are in good condition; the battery may be damaged by being uncharged for so long, but I've never ...


16

The reason I would connect the positive cable first (in a negatively-earthed car) is that while tightening the positive connector with a spanner (wrench), if I were to touch the body of the car with the spanner at the same time, nothing would happen and I would be OK. However if the negative was already connected to the battery and I shorted the positive to ...


14

Sure you could put a bigger battery in .What may happen is that the total proposed draw is too much for the dynamo and it will go flat.Even if it does not go flat because your appliance usage patterns are intermittent you will get a lower battery life because of the constant cycling .If dealing with the charging system is too hard or too expensive then ...


13

You don't need to solder them, clean the terminals really well and apply some dielctric grease or buy some battery terminal protector, this is a spray that you can spray on the terminals and this will keep the battery form corroding. I personally use heavy duty bearing grease to apply over and around the terminals, this helps really well keeping the ...


13

Your question is difficult to answer without you knowing the inner workings of an alternator. The basics. If you move a magnetic field near a coil of wire the electrons in the wire get exited and electricity will be made. The amount of electricity made depends on the size of the magnetic field and its speed. The bigger the field and the faster it's moving ...


12

This step is a carryover from days gone by and is not needed in modern vehicles. Batteries from 50 or 60+ years ago were not as powerful or reliable as modern ones. Older batteries had difficulty handling the load of the starter motor alone. Engines cranked longer before starting and were cranking large displacement engines. Any added load from wiper, radio ...


12

tl dr: Corrosion (once cleaned) is not a huge issue. It is just typical corrosion on the battery terminal. See this image: (NOTE: This is a 6V battery, but the same principles apply.) The blueish color you see is hydrated copper sulfate. When acid vapors escape from the battery, it can cause a reaction with any copper which may be in the terminal. The ...


12

Lead acid type batteries, such as this, like to be charged very slowly. Under 5 amps for many hours would be best. During fast charging the internals overheat and electrolyte can boil. Best to charge slowly if time allows. This type battery has its worst damage happen when it is stored discharged. The chemistry in this state is more acidic. This acid ...


12

I can't give you numbers or calculations without some work, but I can tell you than energy is never free. Cars have an A/C compressor that is mechanically driven by the engine because this is the easiest way to get the job done in a typical consumer car. An A/C compressor actually takes a huge amount of energy to operate. In fact a central A/C unit for a ...


10

IIRC, the Prius has a step down voltage regulator which charges the 12v battery from the main power. I'd bet this system is having an issue and is not charging the battery. As for the 12v battery. I'd bet the old battery (the first replacement?) is good, but has dropped in voltage below what the charger can deal with. To overcome this, you need a second ...


10

This battery pack is rated for 4A at 12V. But a really empty car battery can easily draw much more that 5A when connected to 12V, which is definitely too much for your battery pack. The LiPo battery itself can deliver lots of, but not unlimited current. At high currents, it can get really hot and even start a fire. The battery pack contains a protection ...


9

The starter circuit should only draw whatever current it needs so the excess shouldn't cause any problem.


9

The two biggest disadvantage of lead acid batteries compared to the newer types like Li Ion are that they are heavier, and that they contain liquid acid. Another possible issue is that they can produce hydrogen gas. On the other hand, they are very inexpensive, have a long life expectancy, have a very high tolerance for overcharging without being damaged, ...


9

Yes its possible to start a car with Ultra capacitors. These caps don't appear to have a cycle life that the traditional lead acid batteries have. The ability of these caps to provide starting current is very good. There are a couple of snags: The caps at present are more pricey than the best lead acid batteries. The caps are strung in series to get the ...


9

As long as it is not overcharging your battery, it will increase the useful life of the battery. The reason behind this is, as a battery sits, it loses power. Some of the electrolysis which goes on to make a battery work, also breaks down the battery. During this period, the battery goes through a sulfating period, where sulfur crystals grow on the lead ...


9

A @FredWilson says, you need to charge it slowly - either by driving it around or by using a trickle charger. If you can get a trickle charger with a 'maintenance mode', you can leave it permanently attached to the car and it will keep the battery topped up and stop it going flat in the first place. If possible, I'd also recommend finding someone you trust ...


9

Well, Teslas (and presumably other all-electric cars) have A/C so it's not impossible, but A/C takes a fair amount of power. On the other hand, Teslas store a lot of energy. The A/C is something like 2.4kW which is about 8,000 BTU/h or about 3HP. So using an electric motor on a conventional car might give you a few more HP briefly, but the alternator has ...


8

Gloves are not essential, but highly recommended When replacing a car battery there are three potential hazards that relate to safety: electrical hazard - the battery is capable of generating 100's of amps' worth of current. You want to avoid shorting the two terminals with something like a wrench, cable or hand jewellery. In this regard, gloves can help ...


8

The Voltage levels let you know how much charge is present in the battery thus warning you before the entire thing drains out. For example the below information is for the standard car battery which starts the car, works the steoreo etc , not the additional equipments like on the ambulance. 12.66v . . . 100% Charge 12.45v . . . 75% 12.24v . . . 50% ...


8

Since you have a battery which isn't that old (most batteries have about a five year life span), I'd suggest you put it on a charger and try to recharge it. This will allow the battery to come back to full charge without putting an undue stress on your alternator. You have to decide if the time spent in recharging the battery is worth your time. To me, ...


8

I think you have an issue with the way you are thinking. You are describing the issue as if the batteries are hooked up in series. In that case, yes there'd be a huge back current going on. Both batteries would be made into a complete circuit and you'd have global thermal nuclear meltdown (or whatever the car battery equivalent would be). This is not the ...


8

Yes, as everyone is stating, a spark igniting hydrogen gas could cause an explosion, causing injury from small parts, sulfuric acid or both. Very nasty. Hydrogen gas is a byproduct of electrical energy created from a chemical reaction of lead plates submerged into the acid and water. Sparks can happen internally, too. Like when the lead plates warp from ...


8

A battery that has an internal electrical short, usually one of the plates has come loose and is touching its neighboring plate will cause the alternator to work much harder than normal. This can shorten the life of the alternator. This condition is usually discovered quickly as the battery will not function well in this case. When alternators or motors ...


8

The short answer to your question is no. As @JPhi1618 noted, the compressor is mechanically driven. Without the compressor you don't have any cooling. The AC runs by changing the state and pressure of a liquid, and compressing the liquid is a big part of that cycle. If you bolted an electric compressor onto the car you would have to find a way to switch ...


7

Two reasons: To reduce the possibility of short-circuiting the battery by removing the connection to 'ground' To make sure everything is switched off and unable to function while you're working on it. You don't want, for example, the electric fan to suddenly kick in while you've got your hands in there...


7

You should not incur any issues using a secondary battery with a battery isolator. It will not cause any damage to your alternator. For your edification, it won't be using wasted energy, but your engine will probably using a tad more gas to operate the alternator, which will have to do more work. On a side note, you might want to rethink exactly what you ...


7

No. Your 12V socket is designed to deliver 12V, at a current described in your car manual. Most of my 12V sockets in the car can deliver up to 5A apparently (haven't tested this though, but I run a 200W invertor when I go car-camping. It is handy for everything) The worst that can happen is if your invertor tries to draw more than the 12V socket is fused ...


7

An insufficiently-charged battery would explain what you're seeing: the unresponsive throttle is because the throttle is electronically-actuated (at least that's what eBay reckons) Not sure about the Sentra, but airbag and engine oil lights can turn on due to insufficient voltage the engine will stall because the fuel injectors need electricity to ...


7

If there is nothing connected to it (which can draw power), no power will be drawn. To me that means there are no drawbacks. I would not have an issue of making the socket as always hot for just the purpose you suggest. NOTE: I don't know what else I can add here.



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